Automatic timing and indexing mechanism for wheel wear adjustment



June 6, 1961 J. ROSS 2,986,854 AUTOMATIC TIMING AND INDEXING MECHANISM FOR WHEEL WEAR ADJUSTMENT Filed Aug. 11, 1958 4 Sheets-Sheet 1 FlG.l.

INVENTOR. JOHN ROSS June 6, 1961 2,986,854

J. ROSS AUTOMATIC TIMING AND INDEXING MECHANISM FOR WHEEL WEAR ADJUSTMENT Filed Aug. 11, 1958 4 Sheets-Sheet 2 FIG.4.

INVENTOR. JOHN ROSS Bwmm; 4

A TORNEYS June 6, 1961 J. ROSS 2,986,854

AUTOMATIC TIMING AND INDEXING MECHANISM FOR WHEEL WEAR ADJUSTMENT 4 Sheets-Sheet 3 Filed Aug. 11, 1958 INVENTOR.

. JOHN R055 5% ATTORNEYS J1me 1961 J. ROSS 2,986,854

AUTOMATIC TIMING AND INDEXING MECHANISM FOR WHEEL WEAR ADJUSTMENT Filed Aug. 11, 1958 4 Sheets-Sheet 4 so I i INVENTOR.

J HN ROSS Byfi/Zzzi w AT ORNEYS 2,986,854 AUTOMATIC TIMING AND INDEXING MECHA- 'NISM FOR WHEEL WEAR ADJUSTMENT John Ross, Detroit, Mich., assignor to Midwest Supply and Manufacturing Company, Ferndale, Mich., a corporation of Michigan Filed Aug. 11, 1958, Ser. No. 754,269 Claims. (Cl. 51--'165) The present invention relates to an improved automatic timing and indexing mechanism for the periodic adjustment of an operating unit, such as a bufling wheel carried by the movable head of an industrial polishing machine, in order to take up for normal wear on the wheel in operation. The improvement takes the form of a motor driven, automatically controlled feed device for the head which may be applied to various bufilng and related type machines; and a typical application is to a machine having head adjusting provisions such as are illustrated and described in the copending application of Otto Thiel, Serial No. 755,620, filed August 18, 1958, now Patent No. 2,947,122, dated August 2, 1960.

It is an object of the invention -to provide a motor driven head adjusting mechanism of the type described, wherein at the commencement of a polishing or like operation, with the buffing wheel and head at one limit of their feed-in movement toward the work, they are periodically advanced automatically toward the work, in small timed and repeated increments of motion, until a position of maximum permissible buflf wear is reached. Thus wear of the buffing wheel is automatically compen sated for until its bufis should be replaced, and the wheel will at all times exert substantially uniform bufiing pressure upon the work at a substantially uniform zone or area of engagement therewith.

Another object of the invention is to provide a motor controlled adjusting mechanism as described, wherein upon the bufling Wheel and head reaching the extremity of their travel toward the work, in the vertical direction in the case of a buffing wheel as herein illustrated, further travel will be automatically halted and the wheel and head will be returned upward to their original posi tion, for replacement of worn wheel buifs as desired.

More specifically, it is an object to provide an adjusting mechanism of this sort which operates a wheel head for longitudinal motion upon an appropriate support, as guided by coacting dovetail type slide provisions. In accordance with the invention, the mechanism comprises a small and compact motor and speed reducer unit applied directly to the means for operating the slide parts, for example a screw shaft rotatably mounted on the movable slide member of the head and in threaded engagement with a fixed nut member on a support. Thus, the electric operating unit travels with the head in the adjustment thereof relative to the work, always in the direction to and from the latter.

The foregoing as well as other objects will become more apparent as this description proceeds especially when considered in connection with the accompanying drawings illustrating preferred embodiments of the invention, wherein:

FIG. 1 is a front elevational view generally illustrating the improved timing mechanism of the invention as applied to a standard upright type of bufiing machine;

FIG. 2 is a fragmentary top plan view, as from line 2--2 of FIG. 1, showing typical wheel mounting and driving provisions of a machine of this sort;

FIG. 3 is a fragmentary view in front elevation, but larger scale than FIG. 1, showing the cam controlled limit switch unit of the invention, as appliedto the movtates Patent able head and fixed slide support of the machine to control the timing motor;

FIG. 4 is a fragmentary top plan view of the limit switch unit thus applied to the machine;

FIG. 5 is a fragmentary view in end elevation, as from line 5-5. of FIG. 3;

FIG. 6 is a top plan view of a reduction gear housing constituting a part of the motor drive unit of the control, being partially broken way and in horizontal section along:line 66 of FIG. 1; and

FIG.. 7 is a schematic wiring diagram of the electrical control circuit of the improved feed mechanism.

Referring first to FIGS. 1 and 2 of the drawings, the reference numeral 10'generally designates a conventional rotary upright bufiing machine, characterized by a base 11, a vertical column 12 adjustable horizontally thereon, a relatively fixed mounting sleeve 13 on the column (having suitable means to adjust it vertically), which sleeve provides an upright fixed slide guide member 14 at one side thereof, and a movable wheel mounting head 15 carried by the guide member 14 for longitudinal ad'- justing movement thereon.

The head 15 rotatably mounts a standard butfing wheel 16, which is journalled in a spindle and belt housing 17 borne by the head 15. Wheel 16 is driven by suitably rated electric motor 18 carried on head 15, with a belt and pulley arrangement (not shown) in housing 17 to drive wheel 16 from the motor. Suitable means are provided, generally indicated at 19, to adjust the entire mounting sleeve and head assembly bodily on column 12, and these provisions, as well as those described above, are entirely conventional. Since they do not concern the present invention, further illustration and description thereof are dispensed with.

An optional spring device 20 and air cylinder 21 may be appropriately connected between fixed bracket structure of the wheel supporting head 15 and the belt and spindle housing 17, in order to control the pressure of the wheel 16 against the work (not shown), which devices are also conventional and constitute no part of the invention.

As illustrated in Fig. 4 of the drawings, the head 15 is provided with a dovetail-shaped slide 22, which is slidably received in an upright way 23 formed on the fixed guide member 14. A threaded screw shaft 24 is rotatably journalled at its opposite ends by the slide 22, being axially restrained by suitable conventional means (not shown), and the screw shaft 24 has threaded engagement in a known fashion with a nut portion on the fixed slide member 14, intermediate the rotatably journalled ends of the shaft. This type of screw and nut actuating means for a slidable head such as the head 15 are well known, and for the purpose of rotatably manipulating it for adjustment the screw shaft 24 is ordinarily provided at its upper end with a squared end formation 26 (see FIG. 6) for the reception of a suitable operating wrench.

Referring to FIGS. 1 and 6, the reference numeral 28 genenally designates a motorized timing and control unit which, in accordance with the invention, is applied directly to and in fixed driving relation to the top squared end 26 of screw shaft 24. In this connection, it is contemplated that the unit 28 may be furnished as an optional adapter unit, i.e., that the machine 10 may be purchased with the unit 28 incorporated thereon as a part of original equipment, or that the machine may be purchased without this unit, the latter being available for later application to convert the machine for automatically timed head adjustment.

To the foregoing ends, the unit 28 may consist of an upright tubular adapter housing 30 having provisions for bolting or otherwise suitably securing the same' to the top of the slide 22 carried by head 15. As shown in FIG. 6, the housing 30 has a bottom flange 31 provided with bolt holes 32 for this purpose.

! A worm gear 33 is suitably journalled on an upright axis in housing 30, with means generally designated. 34 for'connecting this gear in fixed driving relation to the upper squared end '26 of screw shaft 24. As also shown in FIG. 6, a horizontally and transversely extending driving worm shaft 36 is rotatably mounted in housing 30, as by means of roller bearings 37; and a worm 38 is fixed on shaft 36 within housing 30, having mating running engagement with the teeth of the worm gear 33.

At one end thereof, i.e., the left hand end as shown in FIG. 6, the worm shaft 36 projects outwardly of housing 30, where it is provided with a squared end 38' for the reception of an appropriate hand wrench. At its opposite end the shaft 36 also projects outwardly of housing 30, and has a belt pulley 40 secured thereon. Pulley 40 is received in an appropriate shield or housing 41 and has a driving belt 42 trained therearound; and at its upper end the belt 42 engages a suitable pulley fixed on the shaft 43 of an electric motor 44 of suitable rating (-see FIG. 1). This motor is appropriately mounted upon the top of the gear housing 30.

Referring now to FIGS. 3, 4 and in conjunction with FIGS. 1 and 2, the reference numeral 46 generally designates a limit switch and control or tappet unit by which the electrical energization of motor 44 is controlled, thus controlling periodic downward indexing and wear compensating movements of the wheel head 15 and wheel 16 relative to the work. The unit 46 also initiates the return upward movement of the head 15 to its original position after these cycles of motion are completed, as for replacement of worn buffs of the wheel 16.

As shown in FIGS. 3, 4 and 5, the unit 46 comprises a first and lower limit switch 47 and a second and upper limit switch 48, both suitablymounted in fixed vertically spaced relation to one another, as by a bracket 4-9 fixedly connected to a side of the stationary slide support member 14. These limit switches 47, 48 are of the snapover or toggle type, and their respective operating fingers or arms are denoted 50.

In order to operate the switch fingers '50 in the sequence to be described, the boiling wheel head 15 has a bracket 51 fixed to a side thereof to move therewith as guided by slide 22, and this bracket fixedly carries vertically spaced cams or t-appets 52, 53 and 54, in such position that as the head and bracket 51 move relative to the fixed slide guide member 14, the cams 52, 53 and 54 will engage and operate the limit switches 47, 48. This is done in a sequence to be described.

Reference should now be made to FIG. 7 of the drawings, a wiring diagram in which the limit switch components just referred to are conventionally shown, along with other electrical controls. The components are shown in FIG. 7 in their positions and conditions at the commencement of a complete operating cycle of the control mechanism of the invention, i.e., when the head 15 is at the top limit of its vertical travel relative to the work.

The circuit of FIG. 7 essentially incorporates timing and control relays wired with a reversing starter for the control motor 44 of the mechanism. Thus, a first timing relay 56 is shown having a coil operating double acting contacts 56', and a second timing relay mechanism 57 is shown having a motor 58 and a clutch 59, the motor 58 controlling the opening and closing of multiple contacts including the contact members 58', 58".

The circuit of FIG. 7 is electrically supplied through -a suitable transformer 60, and the coil of a control relay 61 is adapted to be connected in series across the terminals of this source by one of two contacts of limit switch 47. The relay 61 controls a normally closed con- 1:101; 61' which is adapted to be connected in series with the .other contact of limit switch 47., Further normally open contacts of relay 61 are designated 61" and 61".

The reference numerals 62 and 63, respectively, desighate the down and up side energizing coils of a reversing starter for the motor 44, and the normally closed contacts 62', 63', respectively, responsive to these coils are electrically connected in the circuit a shown.

The reference numeral 64 designates a reset switch which is operated manually after the head 15 reaches the extreme limit of its upward stroke and is ready to restart; and the reference numeral 65' designates a similar operating switch means which is manipulated to override control operation, up or down, when the head is in any part of its stroke.

In the operation of the mechanism under the control of the circuit shown in FIG. 7, it is to be assumed that the components are in their illustrated positions and conditions when the head 15 is at its top limit. With switch 64 closed and switch 65 open, a circuit is completed through limit switch 47, the contact 61' of control relay 61 and one of the contacts of timing relay 56' to the down" coil of reversing starter 62. A circuit is also completed through the contact member 58' of timing relay mechanism 57 and the coil of timing relay 56. The contacts of timing relay 56 delay predeterminedly in opening as the motor 44, energized by the starter, drives screw shaft 24 to advance the head 15 downwardly in this interval.

As the first contact of timing relay 56 opens, it opens the circuit through down reversing starter coil 62, and closes a circuit energizing the motor 58 and clutch 59 of the timing relay mechanism 57. After a predetermined time, determined by the selection and setting of timing relay 57, its contacts 58' and 58" open, resulting in deenergization of timing relay 56. This in turn results in reclosing of the normally closed contacts of the relay 56 and the opening of the contacts of the circuit of timing relay 57, thus again energizing the down side 62 of the reversing starter.

A repetition of the downward indexing movement of head 15 takes place.

At the bottom of the travel of the head, the central operating cam or tappet 53 (FIG. 3) snaps the finger 50 of bottom limit switch 47 downwardly, thus opening the circuits to both timers 56, 57 and the down side of the reversing starter. Control relay 61 is now energized, sealing it in and energizing the up" side coil 63 of the reversing starter through closed limit switch 48. The head 15 is elevated completely to the top of its stroke, without interruption of its motion by any timing provision, and the tappet 52 then trips the finger 50 of the limit switch 47 upwardly to its normal position. A continuation of the upward travel causes top tappet or cam 54 to similarly trip the operating arm 50 of top limit switch 48, thus de-energizing the up side of the reversing starter. In order to repeat the full cycle, the reset switch 64 is operated.

It is seen that the invention provides a timing control whereby a series of predetermined slight increments of downward travel of the wheel head 15 is produced for the purpose of compensating for wear on the bufling wheel 16. The rate of speed of the downward travel is determined by the selection of the timing relay 56, and the tirne between successive lowering phases is determined by the selection and setting of the timing relay 57. Insurance is had that buffing contact of the wheel 16 with the work will be kept substantially uniform, and at uniform pressure during the entire downward motion of the head.

What I claim as my invention is:

l. A mechanism to control and time the travel of an operating head in engagement with a work piece, comprising a fixed support, a slide having means to connect the same to said head and being slidably guided for, movement on said support, a threaded member rotatably mounted .on and axially. restraine by said. slide, said aesasee member threadedly engaging said support to shift the slide thereon upon rotation of said member, an electric reversing motor, a speed reducer drivingly connected between said motor and said threaded member, and an electric circuit to reversibly energize said motor, including limit switch means on said slide and support sequentially engageable to initiate movements of said slide on said support with said head engaging said work piece.

2. A mechanism to control and time the travel of an operating head in engagement with a work piece, comprising a fixed support, a slide having means to connect the same to said head and being slidably guided for movement on said support, a threaded member rotatably mounted on and axially restrained by said slide, said member threadedly engaging said support to shift the slide thereon upon rotation of said member, an electric reversing motor, a speed reducer drivingly connected between said motor and said threaded member, said motor and reducer being carried by said slide for movement therewith, and an electric circuit to reversibly energize said motor, including limit switch means on said slide and support sequentially engageable to initiate movements of said slide on said support with said head engaging said work piece.

3. A mechanism to control and time the travel of an operating head in engagement with the work piece, which head is provided with a rotary operating device which is angularly adjustable as to the position of its axis by angular adjustment of said head, comprising a fixed support, a slide having means to connect the same to said head and being slidably guided for movement on said support, a threaded member rotatably mounted on and axially restrained by said slide, said member threadedly engaging said support to shift the slide thereon upon rotation of said member, an electric reversing motor, a speed reducer drivingly connected between said motor and said threaded member, and an electric circuit to reversibly energize said motor, including limit switch means on said slide and support sequentially engageable to initiate movements of said slide on said support with said head engaging said work piece, the axis of rotation of said threaded member being in fixed relation to said slide and in 90 relation to the axis of rotation of said operating device in any angularly adjusted position of said head.

4. A mechanism to control and time the travel of an operating head in engagement with the work piece, which head is provided with a rotary operating device which is angularly adjustable as to the position of its axis by angular adjustment of said head, comprising a fixed support, a slide having means to connect the same to said head and being slidably guided for movement on said support, a threaded member rotatably mounted on and axially restrained by said slide, said member threadedly engaging said support to shift the slide thereon upon rotation of said member, an electric reversing motor, a speed reducer drivingly connected between said motor and said threaded member, said motor and reducer being carried by said slide for movement therewith, and an electric circuit to reversibly energize said motor, including limit switch means on said slide and support sequentially engageable to initiate movements of said slide on said support with said head engaging said work piece, the axis of rotation of said threaded member being in fixed relation to said slide and in 90 relation to the axis of rotation of said operating device in any angularly adjusted position of said head.

5. A control and timing mechanism for an operating head characterized by a slide type support upon which the head is mounted for linear adjustment, and a shaft rotatively carried on the head and operatively engaging said slide support to effect said adjustment upon rotation of the shaft, said mechanism comprising an electrically operated motor and speed reducer unit carried on said head and connected directly to said shaft in continuous driving engagement with the same as said head and shaft move linearly on said slide support, and an electrical circuit to successively energize said unit.

6. A control and timing mechanism for an operating head characterized by a slide type support upon which the head is mounted for linear adjustment, and a shaft rotatively carried on the head and operatively engaging said slide support to effect said adjustment upon rotation of the shaft, said mechanism comprising an electrically operated motor and speed reducer unit carried on said head and connected directly to said shaft in continuous driving engagement with the same as said head and shaft move linearly on said slide support, and an. electrical circuit to successively energize said unit, comprising coacting limit switch means on said head and slide support successively engageable during said linear adjustment.

7. A mechanism to time the travel of a butfing or like head toward work, and thereby progressively adjust a work-engaging wheel on the head toward the work to periodically compensate for wear on said wheel, said mechanism comprising motor-operated means to advance and retract said head relative to the Work, and means successively operated by said head to time said advance toward the work in time intervals of predetermined duration, said last named means including an electrical circuit wired to said motor-operated means and having timing means controlling the circuit to determine the duration of intervals between adjustments of said head.

8. A mechanism to time the travel of a buffing or like head toward work, and thereby progressively adjust a work-engaging wheel on the head toward the work to periodically compensate for wear on said wheel, said mechanism comprising motor-operated means to advance and retract said head relative to the work, and means successively operated by said head to time said advance toward the work in time intervals of predetermined duration, said last named means comprising an electrical circuit wired to said motor-operated means and including electrical relay means determining the duration of said intervals. l

9. A mechanism to time the travel of a bufling or like head toward work, and thereby progressively adjust a work-engaging wheel on the head toward the work to periodically compensate for wear on said wheel, said mechanism comprising motor-operated means to advance and retract said head relative to the work, and means successively operated by said head to time said advance toward the work in time intervals of predetermined duration, said last named means comprising an electrical circuit wired to said motor-operated means and including electrical relay and limit switch means determining the timing and duration of said intervals.

10. The combination with a bufling or like operating head having a wheel engageable with a work piece, of means to progressively adjust said head toward the work piece to compensate for wear on said wheel, said last named means comprising a member movable toward said work piece and carrying said head for movement therewith, motor means carried by said member and movable with said member and head, said motor operated means being operatively connected with said member to control movement of the latter, and means electrically controlling said motor means, including an electrical circuit operated in response to said movement to determine the timing and duration of intervals of said movement as said head is advanced toward the work piece.

References Cited in the file of this patent UNITED STATES PATENTS 2,647,272 Holmes Aug. 4, 1953 2,748,546 Lane June 5, 1956 FOREIGN PATENTS 89,285 Switzerland Sept. 16, 1921 

